Plastic straws, drinks stirrers and cotton buds could be banned from sale in England under plans being set out by Theresa May.
The prime minister said plastic waste was "one of the greatest environmental challenges facing the world" and said the UK was taking a lead in tackling the problem.
A consultation on banning the disposable plastic products will launch later this year in an effort to cut the amount of waste which ends up in rivers and oceans.
Together we can effect real change so that future generations can enjoy a natural environment that is healthier than we currently find it
Mrs May urged Commonwealth leaders gathered in London to follow the UK’s example in tackling the problem.
She said: “Plastic waste is one of the greatest environmental challenges facing the world, which is why protecting the marine environment is central to our agenda at the Commonwealth Heads of Government Meeting.
“The UK government is a world leader on this issue, and the British public have shown passion and energy embracing our plastic bag charge and microbead ban, and today we have put forward ambitious plans to further reduce plastic waste from straws, stirrers and cotton buds.
“Alongside our domestic action, this week we are rallying Commonwealth countries to join us in the fight against marine plastics, with £61.4 million funding for global research and to improve waste management in developing countries.
“The Commonwealth is a unique organisation, with a huge diversity of wildlife, environments and coastlines.
“Together we can effect real change so that future generations can enjoy a natural environment that is healthier than we currently find it.”
Around 8.5 billion plastic straws are thrown away each year, potentially contributing to the over 150 million tonnes of plastic in the world’s oceans.
The environmental catastrophe sees a million birds and over 100,000 sea mammals die from eating and getting tangled in plastic waste.
Subject to the consultation, which Environment Secretary Michael Gove will launch later this year, the government is prepared to ban the sale of plastic straws, stirrers and cotton buds in England.
Officials will work with industry to develop alternatives and ensure there is sufficient time to adapt, and will also propose excluding plastic straws used for medical reasons.
Mr Gove said: “Single-use plastics are a scourge on our seas and lethal to our precious environment and wildlife so it is vital we act now.
“We have already banned harmful microbeads and cut plastic bag use and now we want to take action on straws, stirrers and cotton buds to help protect our marine life.
“We’ve already seen a number of retailers, bars and restaurants stepping up to the plate and cutting plastic use, however it’s only through government, business and the public working together that we will protect our environment for the next generation – we all have a role to play in turning the tide on plastic.”
The prime minister has urged all Commonwealth countries to sign up to the newly-formed Commonwealth Clean Oceans Alliance and take action to eliminate avoidable plastic waste.
The £61.4 million package of funding will boost global research and help countries across the Commonwealth stop plastic waste from entering the oceans in the first place.
Louise Edge, senior oceans campaigner at Greenpeace UK, said: “The government has made a strong move on banning some of the most unnecessary single-use plastics.
“Reducing the amount of plastic we’re using and discarding is vital for curbing ocean plastic pollution and this could be the start of the elimination of unnecessary throwaway plastic.
“But it is important that the government follows up by going beyond phasing out plastic stirrers, cotton buds and straws, for those who don’t need them. Other non-recyclable ‘problem plastic’ should also be banned at the earliest opportunity."
Labour shadow environment secretary Sue Hayman said: “Leadership and action on the environment begins at home.
“The government has failed to bring forward a single piece of primary legislation on any of their announcements on the environment, farming or animal welfare since the last election.
“With the UK leaving the EU in less than 12 months, there is a worrying lack of preparation to reassure the public that environmental standards won’t suffer.”